1s20
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(New page: 200px<br /><applet load="1s20" size="450" color="white" frame="true" align="right" spinBox="true" caption="1s20, resolution 2.20Å" /> '''A novel NAD binding ...)
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Revision as of 23:55, 20 November 2007
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A novel NAD binding protein revealed by the crystal structure of E. Coli 2,3-diketogulonate reductase (YiaK)
Overview
Escherichia coli YiaK catalyzes the reduction of 2,3-diketo-L-gulonate in, the presence of NADH. It belongs to a large family of oxidoreductases that, is conserved in archaea, bacteria, and eukaryotes but shows no sequence, homology to other proteins. We report here the crystal structures at up to, 2.0-A resolution of YiaK alone and in complex with NAD-tartrate. YiaK has, a new polypeptide backbone fold and a novel mode of recognizing the NAD, cofactor. In addition, NAD is bound in an unusual conformation, at the, interface of a dimer of the enzyme. The crystallographic analysis, unexpectedly revealed the binding of tartrate in the active site. Enzyme, kinetics studies confirm that tartrate and the related D-malate are, inhibitors of YiaK. In contrast to most other enzymes where substrate, binding produces a more closed conformation, the binding of NAD-tartrate, to YiaK produces a more open active site. The free enzyme conformation is, incompatible with NAD binding. His(44) is likely the catalytic residue of, the enzyme.
About this Structure
1S20 is a Single protein structure of sequence from Escherichia coli with TLA and NAD as ligands. Full crystallographic information is available from OCA.
Reference
A novel NAD-binding protein revealed by the crystal structure of 2,3-diketo-L-gulonate reductase (YiaK)., Forouhar F, Lee I, Benach J, Kulkarni K, Xiao R, Acton TB, Montelione GT, Tong L, J Biol Chem. 2004 Mar 26;279(13):13148-55. Epub 2004 Jan 12. PMID:14718529
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